1. Field of the Invention
The present invention relates to a filter mounting device for a vacuum cleaner, and more particularly, to a filter mounting device constructed such that only after a filter for after first collecting foreign materials to be sucked in a cyclone mode and then collecting fine dusts has been mounted within a dust collecting casing, the dust collecting casing can be mounted within a main body of the vacuum cleaner.
2. Description of the Prior Art
FIG. 1 shows the constitution of a general vacuum cleaner. As shown in the figure, the vacuum cleaner comprises a main body 1 with a suction device for sucking indoor air installed therein and a suction portion 2 into which the air is introduced from a floor of a room by suction force generated from the main body.
The main body 1 includes a lower body 5 for installing the suction device therein, and an upper body 6 which is engaged with an upper portion of the lower body 5 and in which a control portion (not shown) for controlling the vacuum cleaner is mounted. A plurality of wheels 8 are installed at a lower side of the main body 1 for allowing the main body 1 to smoothly move on the floor. A discharging portion 8a is formed in each of the wheels 8 for discharging air, from which foreign materials are removed after the air has been introduced through the suction portion 2, from the main body 1.
Between the main body 1 and the suction portion 2, a suction hose 3b made of flexible material, an operation portion 4 connected to an end of the suction hose 3b for allowing a user to operate the cleaner, and an extension pipe 3a for interconnecting the operation portion 4 and the suction portion 2 are sequentially installed.
When electricity is applied to the vacuum cleaner via a wire 9 electrically connected to the suction device contained within the main body 1, the vacuum cleaner is in a standby state. At this time, when the user adjusts suction steps by using buttons on the operation portion 4, the suction device contained within the main body generates suction force corresponding to each suction step. The suction force generated from the suction device is exerted on the suction portion 2 via the suction hose 3b and the extension pipe 3a. By means of the suction force exerted on the suction portion 2, the air containing foreign materials such as dusts are introduced, and the foreign materials in the introduced air are filtered out by a dust collecting unit A. The air from which the foreign materials are filtered out is discharged to the outside of the main body 1 through the discharging portion 8a. Thus, cleaning is performed while going through the above processes.
As described above, the dust collecting unit A is a major component for filtering out the foreign materials contained within the air introduced through the suction portion 2. The dust collecting unit A is also mounted in a receiving space formed between the lower body 5 and the upper body 6.
FIG. 2 is an exploded perspective view of the dust collecting unit, illustrating in detail the dust collecting unit A which has been explained briefly with reference to FIG. 1. As shown in the figure, the dust collecting unit A includes a casing 7 with a top portion thereof opened, a cover 11 for opening and closing the top portion of the casing 7, and a filter 12 mounted below the cover 11.
The filter 12 is constructed such that a top surface 12a formed on the top of the filter can be fitted into or detached from a coupling portion 11a formed on a bottom surface of the cover 11. The cover 11 for mounting the filter 12 opens and closes the open top portion of the dust collecting casing 7.
A handle 7b is constructed to be formed on a rear surface of the casing 7 so that the user can grip the dust collecting casing 7. A frame portion 7f with an operation hole 7g included therein is formed above the handle 7b. An operation member 7i is installed in an inner space of the frame portion 7f, and an operation button 7a of the operation member 7i is installed to protrude through the operation hole 7g. An elastic body 7s is installed below the operation button 7a′. Accordingly, the operation button 7a is always elastically supported within the frame portion 7f in an upward direction by the elastic body 7s. A catching protrusion 7c is formed on the operation member 7i and is elastically engaged with an inlet projection 6t of the main body 1 of the cleaner.
In order to prevent the operation member 7i from coming off from the interior of the frame portion 7f, a cover 7d is fixed to an upper portion of the frame portion 7f. 
In order to mount the dust collecting unit A constructed as such into the main body 1 of the cleaner, the operation button 7a above the handle 7b formed at the rear surface of the casing 7 is pushed into the receiving space in a state where it is pressed down. Then, if the operation button 7a is set free, the catching protrusion 7c is caught into the inlet projection 6t of the upper body 6. Thus, the dust collecting unit A is kept to be coupled to the main body 1.
Here, it can be seen that the dust collecting unit A can be mounted to the main body 1 of the cleaner regardless of whether the filter 12 has been mounted to the cover 11. That is, according to a conventional filter mounting structure, the cover 11 can be mounted on the casing 7, even though the filter 12 has not been mounted to the cover 11. Thus, even though the filter 12 has not been mounted on the cover due to the user's error, the dust collecting unit A may be inadvertently engaged with the main body of the vacuum cleaner.
The dust collecting unit A performs a primary dust collecting function in a cyclone mode that large foreign materials drop down while air introduced through an inlet 11c is formed into a swirl flow within the casing 7, and a secondary dust collecting function that fine dusts are filtered out through the filter 12 after relatively large foreign materials have been filtered out.
As described above, if the filter 12 is not mounted to the cover, large dusts in the air introduced through the inlet 11c drop down by their own gravity from the swirl flow and are deposited onto a separation plate 7m. However, the fine dusts are introduced through an outlet 11b into the main body 1 without being filtered out. Accordingly, it may causes a problem related to cleaning efficiency in that the fine dusts and the like are substantially not filtered out. Further, inner parts may get out of order since the fine dusts flow into the main body of the cleaner.
Furthermore, according to the conventional structure of the vacuum cleaner, even though the vacuum cleaner is operated in a state where the filter 12 is not mounted to the cover as described above, there are no devices for informing the user of this state.